To appreciate the innovative attributes of this invention, it is important to distinguish between paper-punch devices that produce slits and those that produce slots. In a slit, the paper is simply cut along a line segment, and no paper material is removed from the sheet. The edges of a slit touch each other. In a slot, the paper is cut according to an approximate rectangular shape. Paper material is removed and the edges of the slot do not touch each other. Because of their greater opening, a slot is significantly more convenient to use when inserting a business card than a slit. In addition, a slot is less likely to tear since its ends are rounded. While this particular “slit/slot” nomenclature is used in this patent application to distinguish between slits and slots, the prior art does not always make this distinction clearly.
In addition, it is also important to distinguish in the prior art those devices equipped with easily assembled/disassembled hinges from those with fixed hinges. Paper punches equipped with easily assembled/disassembled hinges have the potential of being significantly less expensive to manufacture and to assemble.
None of the devices described in the prior art achieves the combination of economy with functionality that this invention provides.
For example, the invention described in U.S. Pat. No. 914,613 by Storlie benefits from an economical design that consists of a simple rectangular sheet metal plate approximately folded in a springy V-shape and stamped to display sharp edges. When the device is pressed, the sharp edges cut slits in paper.
Another invention by Scalise, in U.S. Pat. No. 4,879,932 describes a paper punching device that produces slits. These slits are produced by “slitting blades” mounted on a first platen, that face “complementary slots formed in a second platen” In addition, the device cannot be easily assembled or disassembled.
The invention described in U.S. Pat. No. 4,893,535 by Bentrim produces slits: the punching element as described in all of its independent claims and in its FIG. 18 is a blade. The hinge used by that device cannot be easily disassembled.
U.S. Pat. No. 4,941,381 by Garner describes a paper punching device that produces slits. This is evidenced by the fact that the cutting element is a blade as described in its claim and in its FIG. 7A.
U.S. Pat. No. 5,611,254 by Rail describes a paper punch capable of making holes in a diversity of shapes including circular, semicircular, triangular and rectangular holes. This device, however, is complex: its hinges are fixed; the punching elements are metal rods as evidenced in that patent FIG. 5. The complexity of the device, together with its form factor which includes a large vertical dimensions gives the device a poor portability.
Hence, there is a need for a device capable of making slots, with a hinge mechanism that can be easily disassembled, and with a high portability.
It is therefore an object of this invention to provide greater safety by replacing tile sharp blade used in most other prior art by a blunt approximately squared-edged male projection that reciprocatingly engages into a female “slot.”
It is an additional object of this invention to punch paper slots rather than paper slits to facilitate mounting of business cards or the like, and to increase the resistance to tears.
It is yet another advantage of this device to be cheaply assembled because of its hinged structure.
Further features, aspects, and advantages of the present invention will be more fully understood when considered with respect to the following detailed description, claims and accompanying drawings.